title: Turbo-FLASH based arterial spin labeled perfusion MRI at 7 T.
abstract: Motivations of arterial spin labeling (ASL) at ultrahigh magnetic fields include prolonged blood T1 and greater signal-to-noise ratio (SNR). However, increased B0 and B1 inhomogeneities and increased specific absorption ratio (SAR) challenge practical ASL implementations. In this study, Turbo-FLASH (Fast Low Angle Shot) based pulsed and pseudo-continuous ASL sequences were performed at 7T, by taking advantage of the relatively low SAR and short TE of Turbo-FLASH that minimizes susceptibility artifacts. Consistent with theoretical predictions, the experimental data showed that Turbo-FLASH based ASL yielded approximately 4 times SNR gain at 7T compared to 3T. High quality perfusion images were obtained with an in-plane spatial resolution of 0.85×1.7 mm(2). A further functional MRI study of motor cortex activation precisely located the primary motor cortex to the precentral gyrus, with the same high spatial resolution. Finally, functional connectivity between left and right motor cortices as well as supplemental motor area were demonstrated using resting state perfusion images. Turbo-FLASH based ASL is a promising approach for perfusion imaging at 7T, which could provide novel approaches to high spatiotemporal resolution fMRI and to investigate the functional connectivity of brain networks at ultrahigh field.
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China. ztzuo@bcslab.ibp.ac.cn
authors.forename: Zhentao
authors.initials: Z
authors.lastname: Zuo
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Rong
authors.initials: R
authors.lastname: Xue
authors.forename: Keith S
authors.initials: KS
authors.lastname: St Lawrence
authors.forename: Danny J J
authors.initials: DJ
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology*; D002536:Cerebral Arteries / Q000033:anatomy & histology / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008962:Models, Theoretical; D009044:Motor Cortex / Q000033:anatomy & histology / Q000098:blood supply / Q000502:physiology; D010477:Perfusion; D015203:Reproducibility of Results; D013113:Spin Labels
chemical_list: D013113:Spin Labels